The invention relates to the antigens obtained by expression of nucleotide sequences or by chemical synthesis, for example using Applied Biosystems brand synthesizers, present in HIV-1 group (or subgroup) O variants and more particularly the antigens corresponding to those which may be isolated from viral particles. By way of example of HIV-1 viruses of the subgroup O, reference is made to the HIV-1(VAU) isolate and to the HIV-1(DUR) isolate.
The invention also relates to monoclonal or polyclonal antibodies induced by these antigens.
The invention also relates to cloned DNA sequences either having sequence analogy or complementarity with the genomic RNA of the abovementioned virus. The invention also relates to processes for the preparation of these cloned DNA sequences. The invention also relates to polypeptides containing amino acid sequences coded for by the cloned DNA sequences.
Furthermore, the invention relates to applications of the antigens mentioned above to the in vitro detection in at-risk individuals of certain forms of AIDS and, as regards some of them, to the production of immunogenic compositions and vaccinating compositions against this retrovirus. Similarly, the invention relates to applications of the abovementioned antibodies for the same purposes and, for some of them, to their application to the production of active principles for medicinal products against this human AIDS.
The invention also relates to the application of the cloned DNA sequences and of the polypeptides obtained from these sequences as probes or primers for gene amplification, in diagnostic kits.
The invention also relates to antigenic compositions which may be obtained by chemical synthesis or by expression in a recombinant cell host and which allow the diagnosis of an infection due to a human retrovirus of HIV type independently of the HIV-1 or HIV-2 subtype. Such compositions comprise at least one peptide chosen from the antigenic peptides common to the HIV-1, HIV-2, HIV-1(DUR) and HIV-1(VAU) viruses or variants of the antigenic peptides possessing similar immunogenic characteristics.
The invention is also directed toward compositions which allow the specific diagnosis of an infection due to a human retrovirus of HIV-1 type, more particularly HIV-1, group M, HIV-2 or HIV-1 group (or subgroup) O and comprising at least one antigenic peptide specific for the HIV-1 virus, an antigenic peptide specific for the HIV-2 virus and an antigenic peptide specific for the HIV-1 group (or subgroup) O virus or variants of these antigenic peptides possessing similar immunogenic characteristics. More particularly, the antigenic peptides are derived from the envelope protein of HIV-1 group M and HIV-2 and HIV-1 group (or subgroup) O viruses.
The invention is moreover directed toward a peptide allowing detection of anti-HIV antibodies which the peptides of the prior art did not always make it possible to detect, based in particular on the discovery of a new HIV-1 strain: HIV-1 DUR. The antiserum directed against it does not always have reactivity with the peptides of the consensus HIV as it is used nowadays. The term xe2x80x9cconsensus HIVxe2x80x9d refers to the regions which are conserved between isolates and whose demonstration is essential to the design of diagnostic reagents or vaccines, and whose mutations impart resistance to antiviral medicinal products. The term xe2x80x9cpeptidexe2x80x9d used in the present text defines both oligopeptides and polypeptides.
Two types of human immunodeficiency virus (HIV) which have responsibility for the development of an LAS or AIDS have been isolated and characterized. A first virus, known as LAV-1 or HIV-1, was isolated and described in GB patent application 8324,800 and patent application EP 84401,834 of Sep. 14, 1984. This virus was also described by F. Barrxc3xa9-Sinoussi et al. in Science (1983), 220, 868-871.
The type 2 HIV retrovirus belongs to a separate class and has only a limited immunological relationship with type 1 HIV retroviruses. HIV-2 retroviruses have been described in European patent application No. 87,400,151,4 published under the number 239,425.
The HIV-1 retrovirus is the most common and its presence is predominant in several regions worldwide. As regards the HIV-2 retrovirus, it is most often found in West Africa, although its propagation outside this region has recently been documented by Grez et al., (1994) J. Virol. 68, 2161-2168.
The totality of primate immunodeficiency lenti-viruses, comprising the type 1 and type 2 human immuno-deficiency viruses as well as several types of non-human primate viruses, is increasing in size and complexity. The most common of these viruses, HIV-1, is currently spreading in the form of a worldwide epidemic and is responsible for a major public health problem. Shortly after the identification and molecular characterization of this virus, it was recognized as being highly variable, and currently comprises several subtypes (Myers, 1994, Louwagie, et al. 1993, Louwagie et al. 1992, Myers, G. (1994) HIV-1 subtypes and phylogenetics trees. In: Human Retrovirus and AIDS 1994; Myers, G., Korber, B., Wain-Hobson, S., Smith, R. F. and Pavlakis, G. N., Eds. Los Alamos National Laboratory, Los Alamos, N.M. III-2-III-9.). This differentiation of subtypes is mainly based on the divergence of the gag and env genes. At least 6 subtypes have been identified, designated A to F, but several are still likely to emerge from the ongoing extensive worldwide survey on the isolates of HIV-1. It has been found that these various subtypes are equidistant from each other, in a phylogenetic profile termed star phylogeny, which suggests that the various HIV-1 subtypes might have evolved and diverged synchronously from a common ancestor.
Recently, two separate viruses of this group of HIV-1 viruses were isolated and characterized. These two viruses were obtained from patients living in Cameroon, in West Central Africa (Gxc3xcrtler, et al. 1994, Vanden Heasevelde, et al. 1994). Their sequence, more particularly the sequence of their env (envelope) gene, shows clearly that these viruses belong to a separate category of HIV-1-related viruses, referred to as HIV-1 group O (Nkengasong et al., 1993).
However, the diversity of the isolates within this group of HIV-1-related viruses is not known, and its propagation outside Africa has not been documented.
A general constraint, in the development of HIV serological tests, is to avoid both falsely positivexe2x80x94or falsely negativexe2x80x94results while at the same time retaining or improving the sensitivity in terms of detection of seropositivity which the previous tests allow.
Tests based on the use of consensus peptide(s), essentially derived from the xe2x80x9cenvxe2x80x9d gene, were considered as an almost ideal solution until the discovery of the HIV-1-O variant brought to light the possibility of falsely negative results (Genomic cloning and complete sequence analysis of a highly divergent African human immunodeficiency virus isolate. J. Virol. 1994; 68: 1586-96; a new subtype of human immunodeficiency virus type 1 (MPV-5180) from Cameroon. J. Virol. 1994; 68: 1581-85).
The non-reactivity of certain tests with xe2x80x9cenvxe2x80x9d peptide antigen, in patients nonetheless exhibiting certain clinical syndromes characteristic of AIDS or lymphadenopathy syndromes which occasionally precede them, is, at the present time, occasionally attributed to an infection of the HIV-1-O group (HIV-1/HIV-2 seronegativity in HIV-1 subtype O infected patients, Lancet 1994; 343: 1393-94; New HIV-1 subtype in Switzerland. Lancet 1994; 344: 270-71).